Two balls are placed near one another and hang down, as shown below.

2 overlapping circles. The left circle is labeled Conduction. The right circle is labeled Induction. An X is in the nonoverlapping part of the left circle.
Which conclusion is supported by this evidence?

Neither ball has a charge.
The balls are both positively charged.
One ball is positively charged, and the other is negatively charged.
Each ball has a charge, but the type of charge is unknown.